Research and Application of Shaft Excavation by Deep Hole One-Time Blasting Technology
Chen Shengyun,
Wang Xueming,
Zhang Ao,
Wu Huajie,
Wang Jing,
Zheng Lei,
Li Fengling
Issue:
Volume 3, Issue 4, December 2018
Pages:
76-82
Received:
15 November 2018
Accepted:
11 December 2018
Published:
14 January 2019
DOI:
10.11648/j.ijmpem.20180304.11
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Abstract: In the construction of subway, tunnel, mining and other underground projects, in order to speed up the construction progress, it is often necessary to excavate a shaft first and then dig at both ends of tunnel at the same time. The shaft excavation is a difficult problem in underground engineering. At present, the shaft excavation construction mainly adopts upward construction method and downward construction method, which are characterized by high labor intensity, high risk coefficient and slow construction speed. In order to realize the efficient excavation of vertical shafts, this paper presents a technology of deep hole one-time blasting into wells. Based on theoretical analysis and practical shaft engineering, the blasting parameters of the deep hole one-time blasting technology are given, such as hole diameter, spacing, layout, charge structure and blasting sequence of each hole, and the technical scheme is formed finally. The technology is applied in a shaft excavation construction in Changping District, Beijing of China and good results are obtained, which proves that the technique is feasible.
Abstract: In the construction of subway, tunnel, mining and other underground projects, in order to speed up the construction progress, it is often necessary to excavate a shaft first and then dig at both ends of tunnel at the same time. The shaft excavation is a difficult problem in underground engineering. At present, the shaft excavation construction main...
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Extraction of Valuable Metals from High-Iron Zinc Sulfide Concentrate by Reductive Leaching
Cunxiong Li,
Chang Wei,
Zhigan Deng,
Fan Zhang,
Gang Fan,
Xingbin Li,
Minting Li
Issue:
Volume 3, Issue 4, December 2018
Pages:
83-90
Received:
29 November 2018
Accepted:
29 December 2018
Published:
29 January 2019
DOI:
10.11648/j.ijmpem.20180304.12
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Views:
Abstract: This study was conducted as part of the development of a new process to recover valuable metals of zinc, copper and indium from high-iron zinc sulfide concentrate (HIZSC) by the reductive leaching of high-iron zinc neutral leaching residue (HIZNLR) with zinc concentrate precipitation of copper with iron powder, neutralization of free sulfuric acid with zinc calcine, precipitation of indium with zinc powder and hematite precipitation to reject iron. Among these stages, reductive leaching is the crucial step, which makes that valuable metals in the materials can be effectively leached and ferric iron in the solution is reduced to ferrous iron. The reductive leachate enables copper, indium and iron separation from the solution in the subsequent process. The results show that by increasing the sulfuric acid concentration, HIZSC addition and prolonging the reaction time, the leaching efficiency of zinc, copper, indium and iron in the sample materials was significantly increased. The maximum metal-leaching efficiency was obtained; 84.3% of the iron was in its soluble ferrous state, and zinc ferrite in the HIZNLR was almost entirely dissolved under the experimental conditions of an H2SO4-to-HIZNLR mass ratio of 1.6, a liquid-to-solid ratio of 11.34 mL/g, a temperature of 90°C, an HIZSC addition of 1.05 times of the stoichiometric amount and a reaction time of 5 h.
Abstract: This study was conducted as part of the development of a new process to recover valuable metals of zinc, copper and indium from high-iron zinc sulfide concentrate (HIZSC) by the reductive leaching of high-iron zinc neutral leaching residue (HIZNLR) with zinc concentrate precipitation of copper with iron powder, neutralization of free sulfuric acid ...
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